Infrared emission from radiatively heated dust possesses general scaling properties. The spectral shape is independent of overall luminosity when the inner boundary of the dusty region is controlled by dust sublimation; the only relevant property of the heating radiation is its frequency profile. For a given type of dust grains, the emission from red giants and supergiants is essentially controlled by a single parameter - the overall dust optical depth. This leads to tight correlations among different spectral properties that explain many available observations and enable systematic studies of large data bases.